Political parties

This 2011 map provided online by the state of Michigan shows Detroit-area congressional districts. Federal judges ruled Thursday, April 25, 2019, that Michigan must redraw gerrymandered congressional and legislative districts for the 2020 election because Republicans configured them to unconstitutionally guarantee their political dominance and dilute the power of Democratic voters. (State of Michigan via AP)

President Donald Trump waves after talking to reporters as he leaves the White House in Washington, Wednesday, April 24, 2019, for a trip to Atlanta with first lady Melania Trump to participate an opioids summit. (AP Photo/Manuel Balce Ceneta)

Democratic presidential hopeful John Hickenlooper, back, hugs Colorado state Sen. Rhonda Fields, D-Aurora, during a meeting with survivors of victims of mass shootings in Colorado Tuesday, April 16, 2019, in Denver. Fields lost her son and his fiancee in a shooting in 2005. (AP Photo/David Zalubowski)

FILE - In this April 2, 2019, file photo, House Oversight and Reform Committee Chair Elijah Cummings, D-Md., speaks on Capitol Hill in Washington. Cummings says the White House is now in “open defiance” of his panel after lawyers advised a former official to resist a subpoena related to the committee’s investigation of White House security clearances. (AP Photo/J. Scott Applewhite)

FILE - In this April 2, 2019, file photo, House Oversight and Reform Committee Chair Elijah Cummings, D-Md., speaks on Capitol Hill in Washington. Cummings says the White House is now in “open defiance” of his panel after lawyers advised a former official to resist a subpoena related to the committee’s investigation of White House security clearances. (AP Photo/J. Scott Applewhite)

FILE - In this April 4, 2019 file photo, Speaker of the House Nancy Pelosi, D-Calif., talks during a news conference on Capitol Hill in Washington. On the same day that House Speaker Nancy Pelosi urged rank-and-file Democrats to proceed with relative caution after the release of special counsel Robert Mueller’s report, Massachusetts Sen. Elizabeth Warren doubled down on her impeachment calls. (AP Photo/J. Scott Applewhite)

2020 Democratic presidential candidate South Bend Mayor Pete Buttigieg speaks during a town hall meeting, Tuesday, April 16, 2019, in Fort Dodge, Iowa. (AP Photo/Charlie Neibergall)

Iowa Rep. Andy McKean, right, the longest serving Republican in the Iowa Legislature says he's becoming a Democrat during a news conference at the Statehouse in Des Moines, Tuesday, April 23, 2019. McKean announced his decision Tuesday, saying one important factor was the presidency of Republican Donald Trump. McKean says he can't support Trump, and if his behavior and leadership is the new normal, "I want no part of it." McKean says he'll register as a Democrat this week and plans to seek re-election as a Democrat in 2020. Listening to McKean from left are, House Minority Whip Rep. Jo Oldson, and House Democratic Leader Rep. Todd Prichard. (AP Photo/David Pitt)

FILE - In this April 19, 2019, photo, Democratic presidential Candidate Sen. Kamala Harris, D-Calif., speaks at the Alpha Kappa Alpha Sorority South Central Regional Conference in New Orleans. (AP Photo/Gerald Herbert)

FILE - In this Sept. 27, 2018, file photo, White House counsel Don McGahn listens as Supreme court nominee Brett Kavanaugh testifies before the Senate Judiciary Committee on Capitol Hill in Washington. Rep. Jerrold Nadler, the chairman of the House Judiciary Committee has subpoenaed McGahn for testimony following the release of the report from special counsel Robert Mueller. (Saul Loeb/Pool Photo via AP, File)